泾阳南塬斜坡地下水位与稳定度的关系研究

发布时间：2018-02-10 01:39

本文关键词： 黄土斜坡地下水位变化稳定度安全水位　出处：《西安科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：泾阳南塬自1976年大面积提水灌溉以来,塬区地下水位逐年抬升,塬边斜坡上滑坡、崩塌灾害频繁发生。基于地下水位监测、地质灾害及其防治资料,运用多学科的理论与方法,系统探索了塬边斜坡地下水位变化与稳定度的关系。主要研究成果如下:(1)塬边斜坡地下水位变化与地质灾害的关联:(1)灌溉活动诱发地下水位上升是研究区滑坡频发的主要诱发因素;(2)自泾阳南塬1976年引水灌溉后,斜坡内的地下水位逐年提升(年均上升量高达2.31m/a),滑坡发生频次及特征分为三个时段:灌溉初期(1976~1980年),灌溉水在斜坡内尚未形成贯通通道,下渗补给地下水方式单一,地下水位平稳,滑坡发生频次仅为一次;大量引水灌溉后(1981~2000年)斜坡内下渗通道形成并逐渐增长,地下水位逐年抬升,20年间发生滑坡26次;2000年以后采取控制措施,塬边斜坡内部地下水位重现平稳期,斜坡趋于稳定期。(2)分析了地下水位变化对塬边斜坡稳定度的影响,一是水位的变化使得斜坡土体强度参数弱化,二是斜坡内部形成渗流产生静水压力以及动水压力,论证了适用于研究区非饱和土斜坡的考虑渗流影响的稳定性评价方法,并以东风村原始斜坡为例进行了理论验证,评价方法及计算公式合理可行。(3)东风村原始斜坡动态渗流场(1992~2003年)的模拟结果:(1)斜坡内浸润线呈现上凸形逐年抬升,浸润锋面不断向坡体前方移动;(2)渗流集中于分层界面向坡外渗流,在坡脚处渗出;(3)最大渗流矢量与水力梯度持续增大,分别由0a时刻(1992年)0.051m/d增大至11a时刻(2003年)的0.137 m/d和0a时刻(1992年)的0.056增大至11a时刻(2003年)的0.193;(4)浸润线上方20m范围内,含水量和孔隙水压受影响很大,而坡顶及远离浸润线20m之外受影响很小。(4)东风村原始斜坡地下水位变化与其稳定度Fs的关系:滑坡稳定度随地下水位抬升逐渐降低的趋势,二者呈较好的线性关系,相关系数R2=0.9655;计算得到东风村滑坡安全地下水位埋深不得低于50.7m,才能保证斜坡的稳定性。
[Abstract]:Since 1976, the groundwater level in the south plateau of Jingyang has been raised year by year, and the landslide and collapse on the slope along the plateau occur frequently. Based on the monitoring of groundwater level, geological hazard and its prevention data, the multi-disciplinary theory and method are used. The relationship between groundwater table variation and stability of slope on the edge of tableland is systematically explored. The main research results are as follows: 1) correlation between groundwater level change and geological hazard of slope on the edge of tableland.) groundwater level rise induced by irrigation activity is the frequency of landslide in the study area. The main inducing factor of the occurrence was after the diversion irrigation in 1976 in the south tableland of Jingyang, The groundwater level in the slope is rising year by year (the annual increase is as high as 2.31 m / a ~ (-1), the frequency and characteristics of landslide are divided into three periods: early irrigation period (1976-#date0#), irrigation water has not formed a through channel in the slope, and the way of infiltration and recharge of groundwater is single. The underground water level is stable, the frequency of landslide is only once, after a large amount of water diversion irrigation, the seepage passage in the slope is formed and gradually increased, the underground water level rises year by year for 20 years, and the landslide occurs 26 times in the past 20 years, and the control measures are taken after 2000. The influence of the change of groundwater level on the stability of slope is analyzed. One is that the soil strength parameter of slope is weakened by the change of water level. Secondly, the hydrostatic pressure and hydrodynamic pressure caused by the formation of seepage inside the slope, the stability evaluation method suitable for the unsaturated soil slope in the study area considering the seepage effect is demonstrated, and the theoretical verification of the original slope in Dongfeng Village is made. The evaluation method and calculation formula are reasonable and feasible.) the dynamic seepage field of Dongfeng Village original slope is simulated from 1992 to 2003. The result of the simulation is: 1) the line of infiltration in the slope is uplifted year by year in a convex shape. The infiltration front continuously moves to the front of the slope body, and the seepage is concentrated on the stratified interface to the outside of the slope, and the maximum seepage vector and hydraulic gradient increase continuously at the foot of the slope. The water content and pore water pressure are greatly affected within 20m above the infiltration line at 0a (1992) (0.051m / d) to 11a (2003) 0.137m / d and 0a (1992) to 11a (1992). The relation between the variation of groundwater level and the stability of Dongfeng Village is: the stability of landslide decreases gradually with the uplift of groundwater table, and the relationship between them is linear. The correlation coefficient R _ 2 ~ (2 +) is 0.9655 and the safe groundwater table depth of Dongfengcun landslide can not be less than 50.7 m to ensure the stability of the slope.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641;P694

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